“If we can derive a model of the intellect, therefore, from the existing literature, it may be suggested that a combination of Spearman’sg, Thurstone’s primary abilities (grouped under mental processes and test material), and the break-down of the IQ into speed, persistence and error-checking, may be the best available at the moment (Eysenck, 1979, p. 193).”

Major Contributions

Highly influential proponent of rigorous, measurement-based approaches to personality research

Established science-based approaches to psychotherapy and clinical training

Defender of the hereditarian position; argued that racial differences in intelligence are partially attributable to genetic factors.

Author of dozens of books (for both academic and popular audiences), and more than 1000 journal articles

Ideas & Interests

From his early interests, it would have been difficult to predict that Hans Eysenck would eventually become one of the world’s most prolific and frequently cited psychologists. He was first attracted to the study of literature and history, and his entry into a psychology program in college was merely a concession to those in authority; he wanted to declare a major in physics, but he did not meet the requirements for admission established by the University of London. Although he was initially disenchanted with his psychology courses, he quickly learned to enjoy the subject (Milite, 2001).

Over the next 60 years, Eysenck published dozens of books and more than 1000 journal articles. His intellectual curiosity about psychological phenomena was wide-ranging. His publications covered an astonishing variety of topics, from personality and intelligence theories to homosexuality, paranormal phenomena, and the causes of smoking-related diseases. This breadth of interest was matched by the unusual depth of his contributions; perhaps no other scientist has contributed so substantially to so many areas of psychology (Mclaughlin, 2000).

Eysenck is most famous for his criticism of psychotherapy (see Eysenck, 1957), his rigorous, measurement-based approach to the study of personality, and for his ability to translate psychological ideas for the popular press. His work on human intelligence is also notable. In 1969, Eysenck’s student Arthur Jensen published a controversial paper asserting that racial differences in intelligence test scores might have genetic origins (Jensen, 1969). Eysenck defended Jensen, and received much criticism in the ensuing controversy. Eysenck later published his own evidence that biological processes might be implicated in racial differences in intelligence (see Eysenck, 1971). By the time he wrote his 1990 autobiography, he had moderated his views to give more weight to environmental influences (Mclaughlin, 2000).

Eyesenck was a proponent of the theory of human intelligence proposed by Donald Hebb and elaborated by Philip Vernon. Hebb called the biological substrate of human cognitive ability “Intelligence A.” When Intelligence A interacts with environmental influences, Intelligence B is generated. Vernon elaborated this view to include Intelligence C, which is what manifests on tests of cognitive ability. This distinction is important for the scientific study of intelligence; Intelligence B is essentially immeasurable due to the large number of confounding variables. Intelligence A is not a concrete “thing” that can be measured, and can only be approached through measures that yield an index of Intelligence C. Intelligence tests, however, are imperfect and vary to the degree that they reflect Intelligence A or B. Eysenck believed that culturally-bounded tests and tests of educational attainment are likely to capture Intelligence B, whereas physiological measures such as positron emission tomography (PET) and electroencephalography (EEG) held more potential as possible tools for capturing intelligence A (Jensen, 1994).